This application claims the benefit of Korean Application No. 00-57866, filed Oct. 2, 2000, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly, to a plasma display panel in which widths of partition walls formed on a substrate are adjusted to be different to secure luminance uniformity.
2. Description of the Related Art
Typically, plasma display panels are image display apparatuses that display desired numbers, characters or graphics by discharging gas injected between two substrates having electrodes to produce ultraviolet rays, and to excite a phosphor layer using the ultraviolet rays produced from the discharge. Plasma display panels can be classified into a direct current (DC) type and an alternating current (AC) type according to a mode of applying a driving voltage to discharge cells (e.g., a discharge mode). Plasma display panels can be further classified into an opposite discharge type and a surface discharge type according to the configuration of the electrodes.
FIG. 1 shows a plasma display panel disclosed in Japanese Patent Publication No. hei 10-241577. Referring to FIG. 1, a plasma display panel 10 includes a front substrate 11 and a rear substrate 12 facing the front substrate 11. Sustain electrodes 13 are formed in a striped pattern on the bottom of the front substrate 11. The sustain electrode 13 is one of a common and scanning electrode, depending on the placement. Bus electrodes 15 are formed on the sustain electrodes 13 to reduce line resistance of the sustain electrodes 13. The bus electrodes 15 are formed of a metallic material having excellent conductivity. The electrodes 13 and 15 are covered with a first dielectric layer 16 on the front substrate 11. A protective layer 17 such as an oxide magnesium (MgO) film is formed on the bottom of the first dielectric layer 16.
Address electrodes 18 are formed on top of the rear substrate 12 and are orthogonal to the sustain electrodes 13. The address electrodes 18 may be covered with a second dielectric layer 19. A plurality of partition walls 100 are formed on top of the second dielectric layer 19. The inner sides of adjacent pairs of the partition walls 100 are coated with red, green and blue phosphor layers 110.
When a predetermined voltage is applied to a panel, the voltage waveform of each electrode 13 is sequentially driven starting from the periphery of the panel. The voltage waveform changes in a discharge space at the center of a substrate 11 due to a voltage drop that occurs due to the line resistance of the bus electrode 15. Accordingly, it is necessary to compensate for the voltage drop at the center of the substrate 11. Moreover, due to a change in a voltage waveform, the luminance is lower at the center of the substrate 11 than at the periphery thereof, resulting in nonuniformity of luminance.
To overcome these problems, the bus electrodes 15 in the plasma display panel 10 are formed to have different widths. In other words, the width of the bus electrode 15 gradually increases (i.e., thickens) from the periphery of the front substrate 11 toward the center thereof so that the line resistance of the bus electrode 15 per unit length decreases from the periphery of the front substrate 11 toward the center thereof. Alternatively, the bus electrodes 15 may be formed to be thicker at the center of the front substrate 11, or may be formed of a material having low resistance.
However, the plasma display panel 10 has the following problems. Generally, the discharge voltage and the luminance are essential to the uniformity of a panel. The panel 10 has a uniform discharge voltage since the resistance of the bus electrode 15 per unit length decreases from the periphery of the front substrate 11 toward the center thereof. However, as the width of the bus electrode 15 formed of an opaque metallic material increases, the opening ratio of a corresponding discharge space decreases. In other words, by forming the bus electrodes 15 to have different widths in order to realize the uniform light emission of the panel 10, a discharge voltage increases from the periphery of the front substrate 11 toward the center so as to improve, which simultaneously decreases the opening ratio to thereby degrade the luminance.
To solve the above and other problems, it is an object of the present invention to provide a plasma display panel with partition walls having different widths on a substrate so as to enlarge a voltage margin and realize luminance uniformity.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the and other objects, a plasma display panel in which partition walls are formed to have different widths according to an embodiment of the present invention includes a front substrate, sustain electrodes formed in a striped pattern on a bottom of the front substrate, a bus electrode formed on a bottom of each sustain electrode, a dielectric layer formed on the bottom of the front substrate to cover the sustain and bus electrodes, a protective layer formed on a bottom of the dielectric layer, a rear substrate disposed opposite the front substrate, address electrodes formed on a top of the rear substrate to be orthogonal to the sustain electrodes, partition walls having different corresponding widths formed on the address electrodes in a direction parallel to the address electrodes to define discharge spaces between corresponding pairs of the partition walls, and red, green and blue phosphor layers deposited between corresponding pairs of the partition walls.
According to an aspect of the present invention, the plasma display panel further includes another dielectric layer formed to cover the address electrodes.
According to another aspect of the present invention, the width of each of the partition walls decreases from a periphery of the rear substrate toward a center in proportion to a voltage drop of the bus electrodes.
According to yet another aspect of the present invention, the discharge spaces gradually become narrower from the center of the rear substrate toward the periphery corresponding to a change in the width of each of the partition walls.